安装 Homestead Vagrant box 时 Vagrant 报类型错误

当我在 windows 上安装 Homestaed Vagrant box 时，报出类型错误，困扰了很久，查找了很多资料，一直都未能解决，有知道怎么解决的吗？执行命令如下：

$ vagrant box add --name laravel/homestead  metadata.json --provider virtualbox
D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/box_metadata.rb:35:in `[]': no implicit conversion of String into Integer (TypeError)
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/box_metadata.rb:35:in `block in initialize'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/box_metadata.rb:33:in `each'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/box_metadata.rb:33:in `map'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/box_metadata.rb:33:in `initialize'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:486:in `new'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:486:in `block in metadata_url?'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:479:in `open'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:479:in `metadata_url?'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:81:in `block in call'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:79:in `map'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builtin/box_add.rb:79:in `call'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/warden.rb:34:in `call'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/builder.rb:116:in `call'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/runner.rb:66:in `block in run'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/util/busy.rb:19:in `busy'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/action/runner.rb:66:in `run'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/plugins/commands/box/command/add.rb:78:in `execute'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/plugins/commands/box/command/root.rb:66:in `execute'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/cli.rb:42:in `execute'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/lib/vagrant/environment.rb:308:in `cli'
        from D:/Vagrant/embedded/gems/gems/vagrant-1.9.1/bin/vagrant:127:in `<main>'